Improvement



L'MG C. ALLlSUN.

' Nut-Lacks.

No. 137,646, Patented Apr'il8, 1873.

WITNESSES. INVENTOR AM PHUTO-L ITHOGRAPH/C 00. M xr ossomvzls Macias:

UNITED STATES PATENT OFFICE.

JOHN MGOALMONT ALLISON, OF SALINA, PENNSYLVANIA.

IMPROVEMENT iN NUT-LCCK$.

Specification forming part of Letters Patent No. 137,646, dated April 8, 1873; application filed February 15, 1873.

To all whom it may concern: I

Be it known that I, J. M. ALLISON, of Salina, in the county of Venango and State of Pennsylvania, have invented a new and valuable Improvement in Combined Spring Bolt and Burr Fastener; and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the an- I nexed drawing making a part of this specification, and to the letters and figures of reference marked thereon.

Figure 1 of the drawing is a representation of a perspective view of my nut-lock. Figs. 2 and 3 are details of the same.

This invention has relation to the class of nut-locks in which a second nut is screwed against the main nut on the bolt, the two nuts, as well as the portions of the bolt on which they respectively work, having their threads turned in opposite directions. The invention consists in forming in the face of the outer nut a recess or cavity of sufficient width and depth to receive the entire body of the inner or main nut, thus allowing both nuts to be screwed down to the same base. The object is to bring the frictional faces of both nuts in contact with each other and with the same bearing-surface-as, for instance, that of the fish-plate, in order that a com'pensatin g effect may be produced upon the two nuts with reference to each other by the shaking or jarring of the plate or bearingsurface.

In the accompanying drawing, the letter A represents a bolt on which is formed a righthand thread, a and a left-hand thread, M. B

indicates an ordinary right hand nut. G is a left-hand nut, in the face of which is formed the recess or cavity 0, of sufficient diameter and depth to inclose the entire body of the nut B when the former nut is screwed down over the latter, the bases of both nuts being thus brought into the same plane, so that they can be screwed tightly against the same bearing-surface, as shown in the drawing, D representing a portion of a fish-plate in contact with an ordinary railroad-rail, E.

What I claim as new, and desire to secure by Letters Patent, is-- A nut with a cavity or recess in its face corresponding with thewidth and depth of a contrarily-threaded nut, so as to be screwed over and down to the same base with the inner nut, substantially as shown and described.

In testimony that I claim the above I have hereunto subscribed my name in the presence of two witnesses.

J. M. ALLISON.

Witnesses GEO. E. RIDGWAY, I. J. MARSHALL. 

